1. Field of the Invention
The present invention relates to pick-up heads that are capable of picking up an object such as a semiconductor chip or die without engaging the active surface of the die. More particularly, the present invention relates to pick-up heads that exert a very large pick-up force that extends over a greater distance than prior art vacuum pick-up tools or pick-up heads.
2. Description of the Prior Art
Heretofore, tools for picking up semiconductor chips could be made from simple tubes attached to a vacuum source. Since such pick-up tools engaged the front active surface of the semiconductor device, the semiconductor device could be damaged during die bonding. One solution to the problem was to make the tip of the pick-up tool from a hard plastic which would not scratch the active surface of the die or chip. Another solution was to grasp the semiconductor device only at its edges and not by its active surface. Such pick-up tools are shown and described in U.S. Pat. Nos. 3,458,102, 3,686,229 and 4,990,051.
Such prior art pick-up tools have been used effectively for producing and packaging integrated circuit devices. However, new large scale integrated devices are being produced which exceed 11/2" on a side and are often made on substrates no thicker than 12 mils. When the thickness of the die needs to be made very thin and the area of the die made very large, it is very difficult to pick up and bond the die with a prior art type die collet without creating a condition that overly stresses the die at the edges or at the active surface.
Accordingly, it would be extremely desirable to provide a contactless pick-up head for picking up fragile die without making contact with the active surface or the edges of the die and have the head or pick-up tool still be able to exert sufficient bonding force on the die to effect die bonding.